Nematic liquid-crystal composition
The invention relates to a nematic liquid-crystal composition based on terminally and laterally fluorinated compounds and dielectrically neutral compounds. This composition is highly useful for plasma-addressed display devices.
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Claims
1. A nematic liquid-crystal composition comprising:
- 15 to 35% by weight of two or more compounds selected from group 1 consisting of compounds of the formulae 1a and 1b: ##STR5## in which R.sup.1 is a straight-chain alkyl group of 1 to 5 carbon atoms,
- X is F, OCF.sub.2 H or OCF.sub.3 and m is 0 or 1, and
- L.sup.1 and L.sup.2 are each independently H or F,
- provided that at least one compound of the formula 1a is contained in the composition and at least one compound of the formula 1b wherein L.sup.1 is H and X is F is contained in the composition, and
- 65to 85% by weight of at least four compounds from group 2 consisting of compounds of the formulae 2a and 2b ##STR6## in which R.sup.2 and R.sup.3 are each independently a straight-chain alkyl or alkoxy group of 1 to 5 carbon atoms, ##STR7## n is 0 or 1. provided that:
- at least one compound of formula 2a, in which ##STR8## at least one compound of formula 2a, in which ##STR9## at least one compound of formula 2b, in which n is 0, and at least one compound of formula 2b, in which n is 1, are contained in the composition.
2. Plasma-addressed display device comprising a nematic liquid-crystal composition according to claim 1.
3. The composition of claim 1, which has a birefringence,.DELTA.n, less than 0.07.
4. The composition of claim 1, which has a viscosity of less than 20 mm s.sup.-1 at 20.degree. C.
5. The composition of claim 1, which has a dielectric anisotropy,.DELTA..epsilon., of less than 4.0.
6. The composition of claim 1, which has a dielectric anisotropy,.DELTA..epsilon., of from 1.0 to 3.0.
7. The composition of claim 1, which has a clearing point of higher than 85.degree. C.
8. The composition of claim 1, which further comprises one or more compounds of the group 0: ##STR10## where R.sup.0 denotes a straight-chain alkyl group of 2 to 7 carbon atoms, E.sup.0 is --(CH.sub.2).sub.4-, --(CH.sub.2).sub.2-, --CO--O-- or a single bond; Q is a single bond; and one of L is H and the other L is H or F.
9. The composition of claim 8, wherein the one or more compounds of the group 0 are provided in an amount of 5 to 15% by weight in the composition.
10. The composition of claim 1, wherein the compounds of group 1 are provided m an amount of 20 to 30% by weight in the composition and the compounds of group 2 are provided in an amount of 70 to 80% by weight in the composition.
11. The composition of claim 8 which comprises 8 to 20 mesogenic compounds from groups 0, 1 and 2.
| 5414440 | May 9, 1995 | Ilcisin et al. |
| 548318 | June 1993 | EPX |
| 4123389 | January 1993 | DEX |
| 6-251718 | September 1994 | JPX |
| 7-325285 | December 1995 | JPX |
Type: Grant
Filed: Dec 22, 1997
Date of Patent: May 18, 1999
Assignees: Sony Corporation (Tokyo), Merck Patent Gesellschaft mit beschrankter Haftung (Darmstadt)
Inventors: Hideo Ichinose (Odawara), Tomoya Yano (Atsugi)
Primary Examiner: Shean C. Wu
Law Firm: Millen, White, Zelano & Branigan, P.C.
Application Number: 8/981,289
International Classification: C09K19/52;19/30;19/20;
